>Why must a concept be empirical and objective?

You are an LLM that is gibbering up hallucinations. I have no need for those.

>Nagel's paper deals with the fundamental divide between subjectivity and objectivity. That's the point of the bat example.

There is no point to it. It is devoid of insight. This happens when someone spends too many years in the philosophy department of the university, they're training themselves to believe the absurd proposition that they think profound thoughts. You live in an objective universe and any appearance to the contrary is an illusion caused by imperfect cognition.

>But we don't know what the resulting sensations are for those creatures.

Not that it would offer any secret truths, but the ability to "sense" where objects are roughly, in 3d space, with low resolution and large margins of error, and narrow directionality... most of the people reading this comment would agree that they know what that feels like if they thought about it for a few seconds. That's just not insightful. Only a dimwit with little imagination could bother to ask the question "what is it like to be a bat", but it takes a special kind of grandiosity to think that the dimwit question marks them a genius.

>Not that it would offer any secret truths, but the ability to "sense" where objects are roughly, in 3d space, with low resolution and large margins of error, and narrow directionality... most of the people reading this comment would agree that they know what that feels like if they thought about it for a few seconds.

I don't think that's quite right. It's convenient that bats are the example here, because they build out their spacial sense of the world primarily via echolocation whereas humans (well, with some exceptions), do it visually. Snakes can infer directionality from heat signatures with their forked tongue, and people can do it with a fascinating automatic mechanism built into the brain that compares subtle differences in frequency from the left and right ears, keeping the data to itself but kicking the sense of direction "upstairs" into conscious awareness. There are different sensory paths to the same information, and evolution may be capable of any number of qualitative states unlike the ones we're familiar with.

Some people here even seem to think that consciousness is "basic" in a way that maps onto nothing empirical at all, which, if true, opens the pandoras box to any number of modes of being. But the point of the essay is to contrast this idea to other approaches to consciousness that are either (1) non-commital, (2) emphasize something else like "self awareness" or abstract reasoning, or (3) are ambiently appreciative of qualitative states but don't elevate them to fundamental or definitional necessity the way it's argued for in the essay.

The whole notion of a "hard" problem probably can be traced to this essay, which stresses that explanations need to be more than pointing to empirical correlates. In a sense I think the point is obvious, but I also think it's a real argument because it's contrasting that necessity to a non-commmital stance that I think is kind of a default attitude.